DENVER—A Colorado woman who won $42.9 million off a penny slot machine saw her jackpot disappear when the casino said the payout message was an error.

Now Colorado gaming authorities are trying to find out what caused the phony fortune.

The false jackpot message went to Louise Chavez Friday while she was playing penny slots in the Fortune Valley Casino in Central City. The machine announced she’d won $42.9 million—a far richer sum than the posted top prize of $251,000.

Fortune Valley doesn’t dispute that the machine told Chavez she’d won millions. But the casino says workers immediately told the gambler the message was an error and reported the mistake to the Colorado Division of Gaming, which regulates casinos.

Chavez says she’s owed the full jackpot. The woman told news stations she earns only about $12,000 a year as a home assistant in suburban Denver.

“I just felt like, you know, I was being cheated. I was being cheated out of the money that I won,” Chavez told KCNC-TV in Denver.

Colorado gaming authorities say the casino has no legal obligation to pay the $42.9 million. Don Burmania, a spokesman for the division, said the top prize of $251,000 was clearly posted in the casino and that a software malfunction is to blame for the glitch.

Burmania said Chavez likely won a prize, triggering the message, but that the game’s structure wouldn’t allow such a rich jackpot.

“If she is owed some money, the casino and the manufacturer are more than willing to pay her what she’s owed. But it will not be $42.9 million, that’s not possible,” Burmania said.

It’s not the first time a Colorado casino has had to fess up to a phony jackpot. In 2008, Burmania said, a penny slot machine at another Colorado casino told a player she’d won $164 million. Her correct prize should have been $6.60.

That casino settled a lawsuit out of court with the gambler.

Chavez says the Fortune Valley Casino gave her a free breakfast but that she is owed more. There was no immediate word on a lawsuit, and casino spokesman Joe Behm said the casino was waiting for the state investigation into the glitch before deciding what to do.

“Of course, once the division’s inquiry is completed, we will follow any instructions we receive,” Behm said in a statement.

Chavez told ABC’s “Good Morning America” that she deserves the full prize.

“There are dreams and there are things I’d like to do—helping my family, helping my kids. That’s why I’m disappointed,” she said.

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